Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
New Member

AIS and LOF errors

Hi guys.

Im having some issues where I get calls dropping in our environment.

After looking at the log file on the gateway (MGCP) I noticed a lot of AIS and LOF errors, which is causing the circuit to flap.

sh controller e1, and sh interface serial0/1/0 did not show any increasing errors, and the controller is up (but as mentioned it flaps)

I did clear the counters on the controller and will look again tomorrow to see if I get any errors.

Normally I would just get the telco to come out and sort the issue, which I did do.

They unplugged our equipment and ran a test (trend/trent test...not sure about the spelling) which showed no errors. Only after plugging our equipment in again are they able to see errors on the line.

This has been a working solution for years now and we havent done any changes in our environment, which makes me think the problem is still on the telco side, but they do have a valid point when they ran their tests and showed that errors only appear on the line if the line in plugged into our equipment.

We have two gateways, both with a PRI connecting to the telco, and both PRI's show the AIS and LOF errors, so I highly doubt a cable or card fault on our equipment.

Aug  7 09:43:39.345 BST: %CONTROLLER-5-UPDOWN: Controller E1 0/1/0, changed state to down (AIS detected)

Aug  7 09:43:39.349 BST: %ISDN-6-LAYER2DOWN: Layer 2 for Interface Se0/1/0:15, TEI 0 changed to down

Aug  7 09:43:40.345 BST: %CONTROLLER-5-UPDOWN: Controller E1 0/1/0, changed state to up

Aug  7 09:43:40.409 BST: %ISDN-6-LAYER2UP: Layer 2 for Interface Se0/1/0:15, TEI 0 changed to up

Aug  7 09:43:50.346 BST: %CONTROLLER-5-UPDOWN: Controller E1 0/1/0, changed state to down (LOF detected)

Aug  7 09:43:50.346 BST: %ISDN-6-LAYER2DOWN: Layer 2 for Interface Se0/1/0:15, TEI 0 changed to down

Aug  7 09:43:51.218 BST: %LINK-3-UPDOWN: Interface Serial0/1/0:15, changed state to down

Aug  7 09:43:57.346 BST: %CONTROLLER-5-UPDOWN: Controller E1 0/1/0, changed state to up

Aug  7 09:43:57.414 BST: %ISDN-6-LAYER2UP: Layer 2 for Interface Se0/1/0:15, TEI 0 changed to up

Aug  7 09:43:59.346 BST: %LINK-3-UPDOWN: Interface Serial0/1/0:15, changed state to up

Any help, or ideas on what could possibly cause these errors on our side would be greatly appreciated.

Thanking in advance.

1 ACCEPTED SOLUTION

Accepted Solutions

AIS and LOF errors

Eugene,

Could you make sure settings on the routers matches what the provider is looking for. You could also use a loopback on your router to make sure the cards are not faulty.

http://www.cisco.com/en/US/tech/tk713/tk628/technologies_tech_note09186a00801069ff.shtml

Please rate useful posts.

Please rate useful posts.
5 REPLIES

AIS and LOF errors

Eugene,

Could you make sure settings on the routers matches what the provider is looking for. You could also use a loopback on your router to make sure the cards are not faulty.

http://www.cisco.com/en/US/tech/tk713/tk628/technologies_tech_note09186a00801069ff.shtml

Please rate useful posts.

Please rate useful posts.
New Member

AIS and LOF errors

Thanks for the link Thomas.
The AIS and LOF messages stopped for a while after the telco tech came to site for the first time and did his tests.

I think it might have been because he unplugged the PRI from our equipment and then plugged it back in again.

Unfortunately the errors returned a day later, so I reported the problem to the telco again only to hear from them that the fault is not on their side...very frustrating working with a telco. So I escalated the matter as high as I could and only then did I get a call from the account portfolio manager and explained to him that the fault is on their side. The account manager conferenced the NOC team into the call and they confirmed that they can see errors on the line.

A quick reset from their side (which took two seconds) and all the errors stopped.

What really grates me is the fact that I had to go through such lengths to get the telco to admit the problem and do something as simple as a reset on the PRI.

Thanks again for the link, which explains all these errors in detail and how to troubleshoot them.

Hall of Fame Super Gold

AIS and LOF errors

That is normal, no telco in the world will ever admit anything is their fault.

New Member

AIS and LOF errors

Hi,

If both E1s come from Telco (PSTN)

Let revise the below diagram:

CPE(E1) ----(4 wires copper)------(E1) Multiplexer ------------ Fiber ----------Multiplexer (E1) ----(4 wire copper)---(Telco)E1 Interface

Your MGCP gateway is CPE, when the fiber broken , you will see AIS, if "4 wire copper" portion between "Multiplexer and Telco E1" broken, you'll see LOF then result in ''AIS".

If you just see "AIS" and "LOF" only , nothing to do on your side.Both alarm coming from Telco area, let report them the issue

Hall of Fame Super Gold

AIS and LOF errors

Seems to be telco fault.

1561
Views
0
Helpful
5
Replies
CreatePlease to create content